China's swimming superstar Sun Yang, Olympic 400m and 1500m freestyle champion, is on the verge of a split with his overseas mentor, Australian Dennis Cotterell, according to Chinese media reporting that Swimming Australia has banned Cotterell from coaching foreign swimmers.

Sun confirmed the potential split but said both he and the coach wanted to continue working together.

"Yes, this is what happened," Sun told media at the Chinese National Championships. "But he still wants to work with me and so do I. We will find out if we can still make it work."

Sun started to practice under Cotterell's guidance at the Miami Swimming Club in Queensland in early 2010 and fine tuned his stroke before breaking Grant Hackett's world mark to take the global 1500m crown in Shanghai last year on his way to Olympic glory in another world-record time.

Sun does not spend the whole year with Cotterell (former mentor to Hackett) and trains for lengthy periods back home in China. 

The same fate may await the partnership of Ye Shiwen, who has trained in Australia and has been a member of coach Ken Wood's squad.

China took the world No 2 spot away from Australia at London 2012, the US still the clear leader and dominant force in world swimming. 

Of his time in Australia, Sun said: "I think the training methods there have fit me very well. I don't want to change anything or find a new place. I wish I could be able to maintain the cooperation with him [Cotterell] and he thinks so too."

According to reports in Chinese and Australian media, Cotterell is said to have picked up more than $500,000 in the wake of Sun's London 2012 success and says China offered him more money in a month to coach Sun than Australia could pay him in a year.

Wood is quoted as saying something similar to the China Daily: "China pays four times what I get from my Australian swimmers. It would frighten you if I told you the amount."